Project XL185/CG250 swap

[XLsior]

Seems my current streak of fails is still ongoing...

had everything done up and back together...

Nice day, so put on the gear jumped on the bike and intended to make a trip down the hill for a fuel tank top up...

Half way down the hill came to a road closed due to repairs so turned around and made the decision to go the long way round...

got back up the hill and came to the interesction....

1st gear clonk no drive in any gear...I pulled over thinking my clutch had just shat the bed...

then I took a look at the rear sprocket and saw it was not rolling with the wheel.

Got off the bike and saw that every sprocket/hub stud had sheared clean...el'cheapos.

I noticed the broken loose studs had semi fallen out and snagged on the sprocket...it was a straight run home so I decided to gun it, knowing anytime I backed off the throttle the studs could fall out and lose drive...

Got close enough home to push the rest of the way up the driveway...

I don't think the universal powers that be wanted me on the road for the last few days...

It might be a spate of bad luck but I often find such things happen for a reason...

Anyway I have 3 sets of original studs form 3 bikes so not lacking spares...the set that failed were chinisium...So moral of the story dont cheap out on running gear.

Going to stick to mowing lawns and drinking beer for the rest of the day...

[XLsior]

After rolling it on stones the fender was scuffed

along with the fact the paint was bubbling, I opted to just go with a respray in 2x gloss black (semi gloss probably a better choice) anyway

paint stripper and pressure washer the bulk of it....

then wet'n'dry sanding back to factory plastic...

then paint...
I'm not trying to get it too perfect as the likelihood of it getting damaged again is a probability...Hopefully it wont bubble and flake/chip off as much.

[XLsior]

The second 81 rolling part XL185 has actually offered some upgrades to the 92...

Parts being some new* cable slide runners.

The 81 had 3 intact runners.

So I took the right upper runner and replaced the left upper runner/choke mount.

The plastic inner rings were also replaced...(my 3dprint attempts didn't hold up)

The chain tensioner block was also in better condition and swapped over...

[XLsior]

After snapping the sprocket drive studs and noticing a clunk It felt apparent the cush hub damper bushings were more than likely the real issue...

So instead of replacing with the usual rubber inner metal outer case I took a chance with these polyurethane dampers listed for cg125/cb100 from Aliexpress.

So off came the rear wheel...again.

An m10 thread tap can be used along with an m10 bolt of same thread pitch to try and push out the bushing. Heat and penertrating fluid might help...

but you will likely just pull out the metal center...flatten an a side and put in vice to remove bolt...

next to remove the rubber a 20mm, 7/8" hole saw bit without the drill bit center is a perfect fit and will take out most of the rubber...

with a dremel/carbide bit cut away the outer race and with a punch and pliers remove the out shell..

clean out install new dampers...

[XLsior]

Can report a much tighter drive engagement response, how long with the red urethane bushings last? guess I'll find out.

[XLsior]

Went for ride to the auto-parts store for some brake cleaner and penetrating/water dispersant fluid

halfway back on the journey home i noticed is was dropping down in power..

hit a steep incline and had to drop gear rapidly to crawl up the slope...

top of the range/hill and more power was being lost...loosing abilty to hold 5th gear...

had to get through a village with traffic...bike would stall out in neutral or clutch pulled in...

the engine was dying and I couldn't stop for fear of not being able to restart.

would cut out and re bump itself in gear...

quater of the way home losing power i was now leaving smoke trails and going uphills in 2nd on the hard shoulder

last intersection before the gun shot back home...couldn't stop at stop sign so had to scrub the ditch and hope to keep any revs on the verge...

Last leg home down hill on the side of the road...1st gear on grass...

bottom of the hill engine dies...push of shame in neutral up the driveway and back home...

engine is smoking hot and the crankcase was puking oil...

poured water over the case to cool it down a bit...hissing steam.

bike cools down..weak compression no start.

Well at least it got me home but Looks like the original pool noodle honed cylinder is also toast.

Project 166fmm swap has just moved up in pecking order.

[XLsior]

The case of the missing intake stud.

Looks like the lower intake manifold stud fell out mid trip and probably created on over lean condition and overheated the head and cylinder...

I don't think i'll be putting to much effort/expense in trying to save the CG.
It was a $80 learning experience plus the failed experiments..

and it got me home......just

kinda sucks...but what can do but take a lesson from it and move on. I will tear down the top end sometime...but I'm over it for now.

Now to see if the $100 loncin 166fmm will play nice.

other than the top mount making fram contact and needing some adjustment with the dremel, its pretty much another bolt in swap.

did the valve lash and while the engine was out put it on the side and inspected the oil screen...which was clean....other than a small metal chunk in the bottom...could it perhaps be a tooth? I hope not.

oil cooler sump adapter was not playing nice...so opted to run without for now until a replacement adapter that threads in without a fight is purchased.

Might use some RTV silcone on those intake studs this time...

[XLsior]

My concerns regarding feul tank clearances has been justified.

the OHC valve and cam timing gear covers do foul on the XL350 custom tank...

The standard 7litre XL185 does not have any issues for anyone looking at doing a OHC chonda swap in an XR200/Xl185 conversion.

So comes the decision to attempt to hammer in a tank clearance solution...if viable.

Or source another CG250.

I am contemplating saving funds for a 172fmm-5 6 speed but If a 166fmm interferes this much how much more tank modification would be required...too much me thinks.

[XLsior]

CG250 postmortem.

blown head gasket into timing cam side...

Fused piston ring...

Dead cylinder

leaky valves...

charred timing gear...

Burnt oil coated valve train...

Connecting rod top end damaged.

Verdict bottom end = spares. Not worth restoring.

Suspect cause: lost lower intake manifold stud...lean burn over heat and fried head gasket...combustion gasses into timing gear/timing side burning oil and pressurized crank case. oil consumption results in more heat and friction...

I'll give it props for running as far as it did with a blown head gasket.

[XLsior]

After getting the loncin in the frame and hooking up all the bits required to get it operational while making some tweaks to the header pipe...

the gear indication sending wire was a plug and play pleasure...good job Loncin for keeping it the same plug/pin configuration.

sloshed a bit 2stroke fuel in the blue tank, attached the PE28FL no issues..

I hit the start button and was greeted with a healthy running engine...

all the gears seemed to select fine...

But....

I think the clutch is non functional...I do have a spare new clutch pack for the CG250 as well as the dead engine itself for parts...

wondering if 166fmm shares the same clutch basket....

Anyway seems my XL185 riding days are on hiatus for the time being.

Think I'll keep an eye out for another used CG250...

[XLsior]

I found 3 Chonda engines up for sale on marketplace about an hour away.

$200 for the lot....

Supposedly 1 ran, 1 smoked and the other was locked up....

A Ducar* OHV ZS167, Zongshen OHC 169FMM and a Loncin 162 OHV 200cc.

The Ducar was apparently the runner case was rough weeping oil either side. Non functional starter motor, missing transfer gear...shifter spline not great.
But its turns over and the pushrods/valves move snd look clean...also had a offset stubby intake manifold in a similar fashion to my modified version...so bonus points.
It is the most abused however, So my plan is to see if its top end will give the cooked CG250 a second wind...

The Zongshen CB250 169FMM was the 'stuck' engine but also clearly the most modern. getting to the flywheel nut with a 14mm I found it freed up going back then hit the top of the piston...rocked back and hit again.
Took the valve covers off and found the intake stuck sprayed some lube on the valve stem top and bottom, with a long 10mm socket over the adjusted gave it a few brisk taps with a hammer...it relented its grip and freed up.
cranked over full revolution on the flywheel nut fine a few times.
some ATF down the plug hole and a compression test using a hot E'start came up with 60psi...not great but has some compression.

Winning.

The Loncin 162 200cc is the 'Smoker' Turned over fine. but has suffered from RTV sealant aplication abuse. also missing starter transfer gear so could not compression test...However as a back up seems to have potential.

[XLsior]

Took the head and cylinder off the Ducar 167.

Cylinder is a bit skanky...has seem some moisture ingress at some point and stained the surface. Some pits, chips and scores...but It feels mostly smooth and looks round...

hot wash and noodle honed...

I decided to try and save my ported head which seems ok after a clean and inspection. No warping or cracks. Picked the best valves from both heads and lapped.

new stem seals and reassemble with the other head's valve assembly.

Found a small crack on the Ducar piston skirt which didn't look bad at first glance...also discovered it only had 1 oil scraper ring installed...

So I ordered a new piston/ring/head gasket kit.

I am opting to try and get the original cooked engine going over the Ducar...Which means trying to salvage the upper rod to accept a new wrist pin...used some 120grit to try and hone the damage without overdoing it...It seemed to accept a pin firmly so I'll run with it until it decides otherwise...

The biggest issue now is the roached timing cam which took the full force of the blown head gasket combustion.

I will have to replace the cam...but it might of heat fused onto the shaft either way I will have to try to get it out.

If not the Ducar Bottom end will take over...internal crank inspect look good but will require parts transfer either way.

[XLsior]

The timing cam shaft thankfully slid out so it was possible to remove the cooked timing gear.

The condition of the Ducar timing gear and cam was good...but for a "runner" it was missing the cam shaft retaining plate....

Marked the timing 'O' each side for an easier alignment with the crank drive gear, as i did not want to mess around with the crank seal.

Timing appears correct.

The cooked timing gear and cam was thrown out. I did also check the profile of the included roller lifter cam...other than being a fraction smaller nothing to me indications a drastic enough change of stock profile cam not to use the roller cam follower lifters...

Any with that all done its a wait for the new piston kit and a hopeful engine resurrection.

[XLsior]

Having started with a 16t/45t with DID plain chain.

then the 17t front for a wider gear ratio and being fairly happy with that...

I also had to think about the chain/ sprockets for my 81 pooched XL185 yard bike...

So I decided to experiment and see if a generic white box ebay 428 X'Ring chain would be an upgrade to the current chain on the Xlsior the 92 road legal bike. Both chains options being roughly the same price...

the chain looks like chain...though I am expecting some stretch.

I also found that an XL100,125,185 share the same rear sprocket dimensions and found a MTX rear 44t was $10 cheaper as a XL100 than an XL185 though having different part numbers...

Any way the rear sprocket looks and fits fine.

So the 81 will get the used non x chain and 45 rear.

Maybe 16t/44t might be my sweet spot for the hills and slopes around my neck of the woods...

then put on the 17t front for distance travel/trips.

[XLsior]

Having experienced catastrophic head gasket failure.

Would like to avoid a repercussion of events while trying to resurrect the engine with donor parts, so spent some time making my own copper head gasket.

Had a sheet of 1mm copper and used a CG250 composite gasket as a stencil.

pictures are fairly self explanatory of the process...lots of filing and used the noodle hone to clean the internal cylinder circumference.